Evaluation of the Use of Shear Wave Ultrasound Elastography for Prediction of Extracorporeal Shock Wave Lithotripsy Outcomes and Renal Calculi Chemical Compositions: A Prospective Study

Purpose: To evaluate the use of shear wave ultrasound elastography (SWUE) in prediction of outcomes of shock wave lithotripsy (SWL) for medium-sized renal stones and to correlate HU and SWUE values with the chemical stone compositions. Materials and Methods: A total of 110 patients with medium-sized renal stones were scheduled for SWL and included. The patients were assessed by non-contrast CT and SWUE. The patients were categorized into two groups: Group A, SWL success, included 80 patients; and Group B, SWL failure, included 30 patients. Baseline data, stone characteristics, and kilopascal (kPa) values were assessed and compared in both groups. Results: The mean age of studied patients was 42.44 ± 11.45 and 43.50 ± 13.20 years in Groups A and B, respectively ( p = 0.679). The mean body mass index of Group A was 25.41 ± 2.93 and Group B was 26.28 ± 2.74 ( p = 0.161). The median (interquartile range [IQR]) of HU of stones was 858.5 (778.0–967.0) in Group A versus 1075.0 (1010.0–1150.0) in Group B ( p < 0.001). The median (IQR) of kPa values of renal stones was 10.05 (8.20–13.0) in Group A versus 18.20 (15.60–19.20) in Group B ( p < 0.001). The median (IQR) of skin-to-stone distance was 85.50 (80.0–92.0) in Group A versus 96.0 (89.0–105.0) in Group B ( p < 0.001). Conclusions: SWUE could be used as a non-invasive and safe alternative method to detect the hardness of stones and predict the outcomes of SWL and the chemical stone compositions.